Abstract
This paper describes a new turning-surface roughness measuring method by slit aperture width vibration in the case of Fraunhofer diffraction. A He-Ne laser parallel beam illuminates the slit aperture formed between a test object and a reference knife edge. This knife edge is sinusoidally vibrated with a stacked piezoelectric element driven by a charge control amplifier. The zeroth order Fraunhofer diffraction light intensity is proportional to the square of the slit width, and this fundamental component intensity of the vibrational frequency is proportional to the slit width. This measurement method is characterized by non-destructive technique and obtaining a surface profile. Measurements are carried out a 2.6μm Rmax turning-surface. The experimental results in the different vibrational amplitude and frequency show the same surface profile, and this method, a stylus instrument and the previous measurement method have the same surface profile.
